FLOOD03331

• County: Gunnison
• Community: Uncompahgre Valley
• Basin: Gunnison
• Title: Uncompahgre Valley Reclamation Project - Hydropower - Part 3 - Environmental Impact Statement DRAFT
• Date: 4/19/1989
• Floodplain - Doc Type: Project

CHAPTER 1

PURPOSE AND NEED

Uncompahgre Valley Reclamation Project

The Gunnison Tunnel, the South Canal, and the AB Lateral of the
UVRP would be used by the proposed development to deliver water
for hydropower generation. A detailed description of the
modifications to these features is presented in chapter 2 of this
report.

The Gunnison Tunnel is now operated during the irrigation season,
with periodic use during the winter months for purposes of
providing water to Fairview Reservoir. With development, the
Tunnel would be operated year round, although periodic inspection
and maintenance would be performed. Year round operation would
not impact the integrity or life expectancy of the Tunnel.
Physical modifications to the Tunnel would not occur in three of
the four development alternatives. For alternative C, the Tunnel
would be modified to increase its hydraulic capacity to
1,300 ft3js.

The South Canal would be modified to incorporate a larger
diversion structure to tbe AB Lateral. These modifications would
be constructed at times which would least disrupt irrigation
deliveries. The construction work would include temporary
provisions for water delivery downstream from the modifications.

A portion of the AB Lateral would be modified to provide greater
discharge capacity in the lateral. The modifications would
include concrete lining of the affected length, estimated to be
approximately 7,100 feet from its diversion at the South Canal to
the proposed penstock intake structure. Irrigation deliveries
would not be impaired during construction of the modifications or
operation of the proposed facility.

Operation of the proposed development would not reduce deliveries
of irrigation water to UVWUA members under any circumstances.
Irrigation water for the Selig, Ironstone, Garnet, and East
Canals would be passed through the proposed facility rather than
the South Canal. Flows in the Uncompahgre River in combination
with Gunnison River water would be used to meet the demands of
the M&D and the Loutzenhizer Canals. However, these systems
would not place a call on the river that would prevent Ridgway
Reservoir from storing water at times when the Gunnison Tunnel
direct flow right could be utilized to meet irrigation demands.

Operation of the proposed development would provide some
insurance against a failure of the South Canal. Acreage
irrigated under the project would not increase.

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